This post is by Tom Herman of The Wall Street Journal.

For most taxpayers, time is drawing short to wrap up the mind-numbingly complex chore of filling out federal income-tax returns and paying whatever is owed to the U.S. Treasury.

But this year some people are eligible for additional time to pay without getting hit by a stiff penalty.

First, some background: In most cases, the official deadline to file and pay is Tuesday, April 17. (It's usually April 15, but that falls on a Sunday this year, and April 16 is a holiday in Washington, D.C.) Those who can't meet the April 17 deadline can ask the Internal Revenue Service for a six-month filing extension. That would give them until Oct. 15 to file -- but it wouldn't give them more time to pay.

Recently, though, the IRS announced plans for "new penalty relief" for some taxpayers who still owe after April 17.

The IRS is granting a new six-month grace period on failure-to-pay penalties for "certain wage earners and self-employed individuals." The request for an extension to pay any taxes owed will result in "relief from the failure-to-pay penalty for tax year 2011 only if the tax, interest and any other penalties are fully paid by Oct. 15, 2012." (Post continues below video.)

This special relief is available to two types of taxpayers. One is "wage earners who have been unemployed at least 30 consecutive days during 2011 or in 2012 up to the April 17 deadline for filing a federal tax return this year." The second is for self-employed individuals who experienced "a 25% or greater reduction in business income in 2011 due to the economy."

But there are strict income limits. "A taxpayer's income must not exceed $200,000 if he or she files as married filing jointly or not exceed $100,000 if he or she files as single or head of household," the IRS says. "This penalty relief is also restricted to taxpayers whose calendar year 2011 balance due does not exceed $50,000."

To seek the 2011 penalty relief, you'll need to fill out a new Form 1127A (.pdf file), available on the IRS website.

But don't expect any relief from interest on the amount owed. The IRS says it still is legally required to charge interest on unpaid back taxes and doesn't have the authority to waive this charge. The rate is currently 3% on an annual basis.

More from The Wall Street Journal and MSN Money:

• Last-minute tax tips
• Tax pitfalls for fund investors
• Frequent-flier tax traps
• Tax refunds aren't evil
• Pick the right tax-return form
• 8 things to do before mailing your return